Sensitivity Analysis and Design Improvement of Contra-Motion Check Valve

This paper presents the design and development of a Contra-Motion check valve for use in pipework of size in the order of 270mm inside diameter. The paper describes the operation of the valve, the fundamental motive force being generated by creating a pressure difference across a piston head, the head being linked by a sensing tube to downstream pressure. This type of valve can provide benefits over the common types of check valves such as: swing, double disc and lift, in that damping is intrinsic to its operation thereby reducing impact on valve seats and eliminating water hammer effects that can be problematic with the other types. Valve characteristics are presented which were generated using Flow Field analysis techniques and also rig testing covering steady state flow conditions. The key factors that affect performance are covered such as: the streamline shape of the structure projecting into the flow, the area difference between the head and piston, and fluid leakage between clearances of parts.